import java.util.*;
class Example2_5 {
  public static void main(String args[]) {
    int start = 0,end,middle;
    int a[] = {12,45,67,89,123,-45,67};
    int N = a.length;
    for(int i=0; i<N; i++) {
    for(int j =i+1; j < N;j++) {
        if(a[j] < a[i]) {
         int t = a[j];
         a[j] = a[i];
         a[i] = t;
        }
      }
    }
    Scanner scanner = new Scanner(System.in);
    System.out.println("输入整数，程序判断该整数是否在数组中:");
    int number = scanner.nextInt();
    int count = 0;
    end = N;
    middle=(start+end)/2;
    while(number!=a[middle]){
        if(number>a[middle])
          start = middle;
        else if(number<a[middle])
          end = middle;
        middle = (start+end)/2;
        count++;
       if(count>N/2)
         break;
    }
       if(count>N/2)
         System.out.printf("%d不在数组中.\n",number);
       else
         System.out.printf("%d在数组中.\n",number);
  }
}
